Previous studies indicate that particle shape plays an important role in the hydraulic conductivity (k) of granular materials, often represented through the Kozeny-Carman (KC) concept. Several recent studies have improved the accuracy of the KC approach using the particle size distribution (PSD) to estimate the specific surface area of particles but overly simplifying the effect of particle shape. This current study innovatively adopts the Micro-Computed Tomography (CT) technique to compute particle shape parameters of different granular materials (e.g., glass beads, sand and crushed gravel) and then incorporate these parameters into the KC equation to estimate k more accurately, which is then validated with experimental data. The results indicate that k varies significantly according to different particle shapes even if the same mean porosity and PSD are retained. Particles that are less spherical and rounded have a larger fluid-particle contact area (i.e., larger shape factor), hence a smaller hydraulic conductivity. The study suggests a shape factor of 1.28−1.52 for natural sand and 1.84−2.1 for crushed sand and gravel can be used for KC method to estimate k while a porosity-dependent equation is proposed to estimate the tortuosity for different shaped materials.

中文翻译：

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颗粒形状对通过Kozeny-Carman方法捕获的颗粒状土壤的水力传导率的作用

先前的研究表明，颗粒形状在粒状材料的水力传导率（k）中起着重要作用，通常通过Kozeny-Carman（KC）概念来表示。最近的一些研究使用颗粒大小分布（PSD）来估计颗粒的比表面积，从而提高了KC方法的准确性，但过度简化了颗粒形状的影响。这项当前的研究创新地采用了微计算机断层扫描（CT）技术来计算不同颗粒材料（例如，玻璃珠，沙子和碎石砾）的颗粒形状参数，然后将这些参数合并到KC方程中以更准确地估算k，然后用实验数据进行验证。结果表明k即使保留相同的平均孔隙率和PSD，根据不同的颗粒形状也会有很大变化。较小球形和圆形的颗粒具有较大的流体-颗粒接触面积（即，较大的形状因数），因此较小的水力传导率。研究表明，天然砂的形状因子为1.28-1.52，碎砂和砾石的形状因子为1.84-2.1，可用于KC方法估计k，同时提出了孔隙度相关方程来估计不同形状材料的曲折度。